> And the worst part is, it's surely conscious on nobody's part. There have even been studies showing this effect.

There are studies showing that the unconscious effect exists. But it's definitely conscious at times.

I know a few people in HR in Silicon Valley, and here are a few things they've heard from actual hiring managers:

"You don't have any kids? Great, we can work you harder!"

"If he had to reschedule the phone interview because his kid is sick, I don't want to move forward hiring him. He obviously has his priorities wrong."

"I don't know, she's at just about the age most women get pregnant. Don't we have a guy we could interview?"

:-(